High-frequency sonic signal transmitter mechanism



T. D.` SMITH Jan. 12, 1965 Filed June '7, 1962 QQ NN w m i w m w, Q N N Mw. 1m Z. Q um NM. m wm w @n n o f 7////////.-//// ///J/ 7 M N .N

United States Patent O 3,165,090 'MGH-FREQUENCY SNIC SGNAL TRANS- MTTER MECHANHSM Theodore D. Smith, indianapolis, ind., assigner to Radio Corporation of America, a corporation of Delaware Fiied .lune 7, 1962, Ser. No. 269,876 6 Claims. (Cl. 116-137) The present invention relates to high-frequency sonic signal transmitters of the unitary portable type now extensively used for remote control of television receivers and the like, and wherein a rod-type transducer or resonator element vibrating in the longitudinal mode is provided for converting7 mechanical energy, imparted thereto by hammer blows, into high-frequency sonic waves or sound signals. These are of predetermined frequency above a normal audible range, for radiation and transmission through the air to operate remote receiver and like control devices which are acoustically attuned and conditioned for response thereto.

A transmitter to which the invention relates thus includes a rod-like body of suitable material adapted to generate high-frequency sonic or like signals or signal pulses preferably above the generally audible sound range and of a predetermined frenquency, by mechanical vibration in the longitudinal mode in response to discrete hammer blows or like mechanical excitation delivered at one end thereof. Each hammer blow generates a train of exponentially-decaying longitudinal vibrations in the rod-like body at the natural longitudinal vibration frequency thereof, which is dependent upon its length and composition. YThe decay time may be controlled by applied damping.

As is known also, the length of the rod or body generally represents one-half wavelength of the fundamental frequency of vibration, and the rod or body is, therefore, held or supported at its center or midway between its ends in a plane normal to the axis and representing a nodal point of minimum vibration or displacement in response to longitudinal excitation. Maximum vibration then occurs at the ends of the rod or body for maximum-anipli- Y tude sonic signal or signal pulse radiation into space. Damping controls the duration of each signal or pulse.

It is an object of this invention to provide an improved actuator or excitation mechanism for a rod-type longitudinal-mode mechanical resonator unit for remote-conftrol sonic signal transmission and the like.

for, of simplified and low-cost construction and -highly resistant to mechanical fatigue and failure in operation.

The actuator or operating mechanism of the present invention, for striking or mechanically exciting sound transducers of the type referred to, is of improved construction. For example it departs from the conventional or established mounting of the hammer or striker means on the free end of a cantilever spring element, which has several disadvantages in structure as well as manufacturing costs.

In accordance with one embodiment of the invention, the

hammer or striker means slides or moves in' a guided path which is aligned with the axis of the transducer rod, and is under control of dual-function hammer-spring means 3,165,090 Patented Jan. 12,1965

vides' improved cooking or loading and triggering actionl compression spring as referred to, which is loaded during A each striking operation. In response Vto release or triggering ofL the hammer by a pawl element, it is driven forward to strike the transducer. The 4spring goes through a short extension and retraction action to withdraw and provide relief for the hammer from the transducer after the striking action. Central guide means for the hammer in coaxial relation to the hammer spring, together with im proved mounting means, may provide further features Vof the actuator or operating mechanism of the present invention. Parallel or divergent directions of movement may be imparted to the hammer means with respect to the slide and driving pawl, for detent or self-tripping of the guided hammer means. In either case a single center guide rod may be provided.

The invention will, however, be further understood from the following description of Acertain embodiments thereof, when considered in connection with the accompanying drawing, and its scope is pointed out in the appended claims.

ln the drawing: FIGURE l is a top or plan view of a high-frequency sonic signal transmitter of the unitary portable type -embodying the invention;

FIGURE 2 is a crosssectional View, and on an enlarged scale, of the transmitter unit of FIGURE 1 taken on the section lines 2 2 thereof, showing various details of construction in accordance with the invention;

FIGURE 3 is a partial sectional plan view of the transmitter unit, taken on the section line 3 3 of FIGURE 2, showing further details of construction in accordance with the invention; and

FlGURE 4 is a longitudinal sectional view, in the manner of FlGURE 2, of a sonic signal transmitter-of the type shown in the preceding gures and illustrating certain modifications thereof in accordance with the invention.

Referring to the drawing, wherein like elements are designated by like reference characters throughoutthe various igures, and referring particularly to FIGURES 1 3 inclusive, the high-frequency sonic signal transmitter shown includes a housing or casing 6, of any suitable material such as metal or plastic and of a size adapted to be held in the hand of an operator. The transmitter casing is provided on one portion thereof, such as the top, with suitable manual operating elements or buttons 7, 8 and 9 which are movable longitudinally of the casing in the present example.

Each button'operates interior sound signal generatingV means of the tuned rod type with longitudinal-mode operation, as shown in FIGURE 2 for the center operating button 8. As is understood, any suitable number 'of operatl ing elements may be provided, depending upon the num- .ber of remote functions to be controlled. Therefore, a description of the mechanism for the one operating element is sufficient for a consideration of the operation of one or more of the elements of such a accordance withthe invention.

As indicated in FIGURE 2, the casing or housing 6 is preferably constructed-in two separable complementary parts comprising a base itl and acover 1l adapted to be transmitter in assembled Vin contacting closed unitary relation as indicat.

of the helical coiled type which is structurally strong and not subject to fatigue after repeated operation. This proed. The casting parts are' further adapted for receiving and holding the'various parts ofthe multi-channelmecha-Y nism, including a resilient mounting block:12of plastic material for an elongated rod-like transducer or resonator i element' 15. The latter extends longitudinally of the casing and is gripped and held in position by a thin circular exible web 16 provided at one face or side of the mounting block l2 and seating in a relatively narrow circumferential mounting groove 17 in the rod l5. A damping which Vis provided with a sound transmitting perforated grille 22., The rearor input end 2i) of the rod is presented for longitudinal-mode excitation or striking by the irnf proved hammer and actuating mechanism located adiacent thereto as shown in FIGURES 2 and 3.

The button S'is slidable longitudinally of the case, as indicated by the arrow adjacent thereto, and is attached as indicated to a longitudinally-movable metallic carrier plate or slide 24, which is held in the retracted position shown,

by a slide return springZS connected between a stud 25 on the slide and a fixed pin Z7 connected with the casing top -portion or vcover 1l. inwhich the slide is mounted. The spring 25 is of the coiledhelical type operating under tension. Theslide 24 thus moves from the position shown,

against the yreturn action of the spring 25 in response to operating movement of the button 8 to the left in the direction of the arrow, as viewed in FIGURE 2.

The rear end of the carrier or slide 24 is provided with two integral down-turned ears or brackets 3% and 3l. A pawl or pawl element v32 is pivoted on the lower side of the slide or carrier 24 ybetween the brackets 3) and 3l,

and isr spring loaded to rotate in a counterclockwise direction by a Vpawl lspring 33. The pawl is substantially rectangular in shape and is pivoted, intermediate between its ends on each side, on integral bearing or pivot pins 34 and iii-i extending laterally therefrom and journaled in the dependentears or bracketelements 3% and 3l respectively; v

vAt an acute angle withrespect to the direction of Amotion of theislide 24, substantially as. shown, the pawl rests at its forward end against'the underside of the slide 24, beingV limited vthereby in .its counterclockwise rotation.

The rear operating end or edge 36 of the pawl 32 rests on the front or forwardside of anannular iiange 37 on the hammer means 33 which is positioned in axial or longitudinal-grelationV to theV transducer rod i at the rear end 20 thereofvas Shown, The hammer means 33 includes a round hammer'or striker #ttl with a convex forwardl face 41,V andis provided with a center or axial opening for a guide pin or vrod 4t2.

The guide pin 42 is secured at one end, in a cantilever manner, to ixed support means, such as a metallic or like still plate d3, rigidly mounted in the base or lower part iti) of the casing. The guide pin passes through the axial hole or opening in the hammer which is made suiiiciently large for the .hammer to slide freely on the guide pin and at the same time is suliiciently Vtight toguide the hammer to axial movement rearwardly in extension of the axis of the resonator element l5. The guide rod d2 and the Y resonator element are thus located in end-to-end relation on substantially the same general longitudinal axis in ..the unit.y Y

krfrhelical coiled compression spring 45 for operating the hammer {it} is also mounted in coaxial relation to the guide pin 42j. This spring is connectedvbetween the hammer and the fixedy support means 43 for the guide pin. ln the 'present example, therear end of Ithe spring is connectedfto a suitablyggrooved guide pin bushing 4 6 at the support d likewise anchored or connected to the hammer, so that the latter is free only to the extent that it can move on the guide rod axis and compressor extend the coiled hammer spring 45.

The tree length of the hammer spring 45 is such that it holds the hammer or the convex face 4l thereof, at a predetermined distance from .the rod or transducer element l5 at its rear end Ztl. The free end d@ of the guide pin 42 is located so that it is on the axial centerline ofthe rod or transducer element l5, without touching the rear end Ztl thereof, but close enough to it so that the hammer 40 cannot fall or move oli the end of the guide pin 42 when the hammer moves forward to strike the rod or transducer element. T he hammer di? and the transducer element l5 are thus heid in spaced end-to-end relation with the mechanism at rest.

When the operating button, such as the button S, is pulled backward in the direction of the arrow, it causes the pawl 32 to move in the same direction, that is, rearwardly and longitudinally of the casing and of the transducer element i5. The pawl, traveling in a fixed longitudinal direction along a horizontal line, pushes against the ilange 37 on the hammer di?, th reby causing the hammer to move back longitudinally and axially with respect to the transducer l5 along the guide pin 4t2.. This movement loads or compresses the hammer spring until the hammer is tripped or triggered by the paw] 32 as the rear edge or operating end 3e moves upwardly along the sloping cam surface of the llange 37, against the biasing action ol the pawl spring 33, until the pawl end 35 rises above the edge of the iiange 3'?, thus releasing the hammer,

ln the present example, release of the hammer by the pawl is caused by tripping 'the pawl against a fixed abutment or finger element 5@ carried by the casing and presently formed as part of or integral with the top or cover portion lll of the casing. This abutment or element is sufhciently narrow, as indicated in FIGURE 3, to enter a central longitudinal slot 5i in the rear end of the slide 2st, so that the forward edge 5?; meets the rearwardmoving pawl 32 and as the slide movement continues, causes clockwise rotation about the pivot pins 34 and 35 to raise the operating end 3e clear of the flange 37, and thereby releasing the hammer which at this point flies forward, guided by the pin 42, until it strikes the transducer l5. When the hammer is released and flies forward it has to overextend the hammer spring 45 to be able to rike the transducer l5. This causes the hammer spring 4S, which functioned as a compression spring when the hammer was being cocked or loaded, to act now as an extension spring which retracts to return the hammer to its normal position of rest as indicated in FIGURE 2. Thus, the hammer ld strikes the transducer l5 only once and does not again engage the transducer rear face or end 2i?, which would cause damping of vibration and result in defective signal output from the transducer l5.

When the operating Vbutton S is released, the sli-de return spring 25, which was extended when the button was pulled to the rear, now causes the button, the slide 2li. and the pawl 3:2 to return to their original positions of rest as shown in FlGURE 2. As the pawl returns, it strikes the rear side of the flange element 37 on the hammer it? and rides up over the iiange to drop down into the engaging or driving lposition shown, with the operating end 3d in contact with the flange 37 on its forward slope or cam face. The pawl is moved into this position by the force of the pawl spring 33 which, as before noted, biases the pawl to rotate in the couuterclockwise direction and bring the stop or opposite end up against the lower side of the slide or carrier 24. The transmitter mechanism is then in condition for a new signal-transmitting cycle oi operation.

From the foregoing description, it will be seen that the elongated rod-like transducer element i5, flexibly supported by the mounting element l2 through the medium of the thin web ld, is tree to vibrate in the longitudinal mode :follow-ing each striking operation and to transmit a sound signal through the forward or grille end of the transmitter to operate any remotely-located device or element (not shown) which is attuned to the natural frequency of operation of the body in the longitudinal mode This may, for example, be in the frequency range of from to 45 kilocycles with an aluminum alloy rod of slightly greater than 3A0 inch in diameter and between two and three inches in length, the showing in FGURE 2 being substantially enlarged to provide greater detail showing of the construction of the transmitter and operating mechanism. The rate of decay of vibration is determined by the position of the damper ring i8, and the mass thereof. However, as both the ring 18 and the mounting means 12 together with the construction of the rod or transducer element do not concern the present invention, further description thereof is believed to be unnecessary. t

In a sonic signal transmitter actuator or operating mechanism in accordance with the invention, it wiH be seen that -in a preferred form, the hammer may have an elongated round head with a circular flange at the rear thereof and is loaded or cocked against the biasing or forward-driving action of a coiled hammer spring along an axis defined by a central guide pin anchored at its rear end in a fixed support means such as a casing element or mass. The cocking action is applied to the hammer `by a spring iloaded pawl or driver element which is mounted on and-moves rearwardly with a carrier or slide underl control of'armanual operating element or button. The hammer spring is substantially free of mechanical failure due to `fatigue in operation over an extended life, .and also functions as a retracting spr-ing for the hammer, while the hammer guiding means may be the single cantiylever mounted guide -pin which passes freely through a central guide opening in the hammer body and to which the hammer body is secured bythe spring. The free end of the guide pin and the face of the hammer, are both `held in spaced relation to and axially aligned with the rear end of the transducer rod or element. The hammer and the transducer element are thus Iin spaced end-to-end relation, with the mechanism at rest.

To simplify the release of the hammer by the slide and pawl operation, the guide pin for the hammer may be placed generally at an angle to the axis of the transducer element and the direction of movement of the slide, but intercepting the axis of the transducer element at a point adjacent to the rear face thereof, as shown in the modification in FIGURE 4, Which may now be considered along with the preceding figures.

In this modification, a cross-sectional view of a transmitter casing 6', similar to that of the preceding figures, isdivided to provide a base portion l0' and a cover portion l1', and in which is mounted the transducer rod l5. The latter is provided with its fiexible mount l2 and damping means 18 as in the preceding modification, whereby it is free to vibrate in the longitudinal mode when struck at the rear end or face 2f? lby the hammer of the hammer means 38, to transmit high-frequency sonic signals forwardly from'the operating end 19 through the front grille 22' of the casing.

The hammer spning surrounds a curved or angled guide rod 42', the forward end of which is in alignment with the axis of the transducer element 15, and the rear end of which is anchored in a fixed support plate 43 secured to the interior of the casing as indicated. An operating button 8 is Connected with a movable slide or carrier 24' to move it rearwardly against a compression slide spring 25. a counter-clockwise direction, engages the flange of the hammer element 40 as in the preceding embodiment, to drive it rearwardly when the slide is operated by the but- Y ton 8. Theguide pin d2' is formed to describe a lateral or downward arc or angular path from its free end to the fixed sup-port plate 43. The hammer, movable on the guide pin, thus travels in a divergent path or direction with respect to that of the slide and the axis of the transducer element.

When the operating button is pulled back toward the hammer the pawl moves in the same direction, as in the preceding embodiment, and travelling in the horizontal line, pushes against the flange on the hammer, causing the latter to move backward against the b-iasing or forward driving action of the hammer spring. The hammer is guided to move back through the arc or angular path provided by the guide pin 42', which is thus at an angle to the axis of the resonator or transducer 15 and t the line of movement of the slideV and pawl. Thus the hammer spring is loaded until it has reached a point Where the fiange on the hammer drops below, or laterally out of, the line described by the movement of the pawl, whereupon the hammer is released to fiy forward through the arc described by the guide pin until it strikes the transducer 15. As in the preceding example, the hammer overextends the hammer spring to strike the transducer and this spring, now acting as an extension spring, withdraws the hammer to its normal retracted position. This prevents the hammer from damping the sound vibrations resulting from the hammer blow, as before, the normal length of the hammer spring being such that it' holds the hammer at a predetermined distance from the transducer or resonator. rThe free end of the guide pin is located so that it is substantially axially aligned with the transducer but spaced therefrom sufficiently closely so that the ham-mer cannot fall off the end of the guide piu.

Yln all other respects the construction and operation of i the modification shown in FIGURE 4 is thesame as tliat of the preceding embodiment, and .the operation of the elements thereof is the same and for the same purpose. As in the preceding embodiment, a plurality of the transducer devices may be provided in a single casi-ng and actuated by separate buttons or other manual control y `means as desired.

A pawl 32', spring-biased to rotate in From the foregoing description, it will be seen that high-frequency sonic signal transmitters of the unitary portable type, operative with transducer or resonator elements vibrating in the longitudinal mode, may be provided with an improved actuator or operatingmechanism, including guided hammer and coiled hammerspring elements operating mainly in compression. The actuator or operating'mechanism shown and described thus departs from the established pivotal mounting of the hammer element on the free end of a cantilever leaf spring which has several disadvantages, structurally and cost-wise, as pointed out. The present mechanism is 'of compact, simplified, Ilow-cost construction, and resilient and effective in operation, thusavoid'ing certain` defects and disadvantages inherent fin the use of conventional devices in this field.

What is claimed is:

l. In a high-frequency sonic signal transmitter, ythe combination with a tuned rod-type longitudinal-mode transducer element of an actuator mechanismrtherefor comprising, a movable hammer positioned in extension of and lspaced from one end of said transducer element, means providing a fixed support in said transmitter, a coiled compression spring connected at one end with said support and at the opposite end with said hammer, a fixed guide rod mounted on said support means for mounting said hammer on said fixed guide rod so thatv ment of said slide, releasing said'hammer to follow said rod guide and strike said transducer element under the force `of `said spring. Y

2. In a high-frequencysonic signal transmitter, the combination with a tuned rod-type longitudinal-mode transducer element,V of an actuator mechanism therefor comprising, a movable hammer positioned in extension of and spaced-from one ,end of said transducer element,

means providing a xed support in said transmitter, a coiled compressiongspringconnected at one end with 'said support and at the opposite end with said harniner, a'pivotally mounted pawl spring biased to engage said hammer, a manually-operable slide for moving said pawl and the hammer to compress said spring and, said hammer having a central opening therethrough, a guide pin extending through 4said opening into close spaced relation to said one Vend ofV the transducer element and being rigidly mounted in connection with said support means at the opposite end for guiding the movement of the hammer with respect to and divergent from the axis of the transducer element and away frorn'said pawl, means on the hammer for receiving the thrust of the pawl andl for effecting. disengagement therewith in re spense to compression of said spring to a predetermined degree, thereby to release the hammer or striking the Yresonator element. 1

3. -In a high-frequency sonic signal transmitter, the combination with a tuned rod-type longitudinal-mode transducer element, of an actuator mechanism therefor comprising, a movable hammer positioned for striking one end of said transducer element, a coiled compression spring fixed in position at one end and connected with said hammer lat the .opposite end, a inanuaily-operable slide having a pivotally-movable paWl for engaging and moving said hammer to compress said spring, means on tlieharnmer for receiving the thrust of the pawl, a i'ixed guide rod,` umean-sfor mounting said hammer on said fixed guide'rod so that said iixed guide lrod guides the movement of said hammer in a predetermined path with respect to and divergent from the path of said pawl, whereby said'hammer and said Vpawl disengage after a predeterminedk movement of-said slide, releasing said hammer to followthe guide rod and strilre said transducer element under the force of said spring.

4, In a Vhigh-frequency sonic signal transmitter, the combination with arod-type longitudinal-mode transducer element, of kan actuator mechanism therefor comprising, a hammer axially spaced from and movable with respect to one end of said transducer element, means including a tixed guide rod for guidingzthef movement of the hammer with respect to and divergent from the axis of thetransducer element, a iixed coiled compression spring surrounding said guide rod and connected Vat ,one end with said hammer to hold.-said hammer retracted from the transducer element, a movable pavvl resiliently engaging said hammer, a manually-operable slide movable froma stop position longitudinally -with respect to the axis of said transducer element for driving said pawl and hammer tocompress said spring, means including a ange on the movement of said hammer and slide in compressing said Cil Cil

spring, thereby to release the hammer for striking the transducer element, and spring means for retracting said slide to said stop position.

, 5. In a high-frequency sonic signal transmitter, the combination with a rod-type longitudinal-mode transducer element, of an actuator mechanism therefor comprising, a movable hammer positioned in erid-toend spaced relation to said transducer element, a coiled compression spring fixed at one end and connected to said hammer at the opposite end, said spring being of a length Aat rest to retract said hammer to said spaced relation with respect to said transducer element, a manually-operable slide movable in substantially-parallel relation to the longitudinal axis of said transducer element means including a fixed pin extending freely through the hammer for guiding the movement of said hammer in a predetermined path with respect to and divergent from the axis of the transducer element and manually operable slide, a pivotally movable pawl mounted on said slide and having an edge positioned to engage said hammer, thereby to compress said spring in response to movement of sai-d slide and, means on the hammer for receiving the thrust of the pawl, said means disengagirig said pawl in response to compression of said spring to a predetermined point of divergence with respect to the direction of the movement of the slide and pawl elements, thereby to release the hammer for striking the transducer element.

6. in a lhigh frequency sonic signal transmitter, the combination with a rod type longitudinal mode type transducer element, of an actuation mechanism therefor coinprising,

a movable hammer positioned for striking one end of said transducer element;

a coil compression spring connected for actuating and retracting said hammer;

a manually operable longitudinally movable slide;

means for guiding the movement of said hammer in a predetermined path including an axial guide opening through said hammer and a fixed curved guide pin extending therethrough into close spaced and to end relation with said transducer element and axially of said compression spring, said hammer guide pin extending from said transducer element in a direction divergent from the axis of said element and the direction of the movement of said slide and pawl element;

said manually operable longitudinally movable slide having a pawl element mounted for engaging and moving said hammer to compress said spring; and said hammer including a ange for receiving the thrust of the pawl element wherein the hammer flange is released from engagement with the pawl element in response to movement of said hammer to a predetermined point of divergence with respect to the direction of the movement of the slide and paWl element.

Referenees Cited in the tile of this patent UNITED STATES PATENTS 

1. IN A HIGH-FREQUENCY SONIC SIGNAL TRANSMITTER, THE COMBINATION WITH A TUNED ROD-TYPE LONGITUDINAL-MODE TRANSDUCER ELEMENT OF AN ACTUATOR MECHANISM THEREFOR COMPRISING, A MOVABLE HAMMER POSITIONED IN EXTENSION OF AND SPACED FROM ONE END OF SAID TRANSDUCER ELEMENT, MEANS PROVIDING A FIXED SUPPORT IN SAID TRANSMITTER, A COILED COMPRESSION SPRING CONNECTED AT ONE END WITH SAID SUPPORT AND AT THE OPPOSITE END WITH SAID HAMMER, A FIXED GUIDE ROD MOUNTED ON SAID SUPPORT MEANS FOR MOUNTING SAID HAMMER ON SAID FIXED GUIDE ROD SO THAT SAID FIXED GUIDE ROD GUIDES THE MOVEMENT OF SAID HAMMER, A PIVOTALLY MOUNTED PAWL SPRING-BIASED TO ENGAGE SAID HAMMER, A MANUALLY OPERABLE SLIDE FOR MOVING SAID PAWL AND THE HAMMER TO COMPRESS SAID SPRING, SAID SLIDE AND SAID ROD BEING RELATIVELY ORIENTED WITH RESPECT TO ONE ANOTHER SO THAT SAID HAMMER AND SAID PAWL MOVE IN DIVERGENT DIRECTIONS AS SAID PAWL MOVES SAID HAMMER IN A DIRECTION TO COMPRESS SAID SPRING, WHEREBY SAID HAMMER AND SAID PAWL DISENGAGE AFTER A PREDETERMINED MOVEMENT OF SAID SLIDE, RELEASING SAID HAMMER TO FOLLOW SAID ROD GUIDE AND STRIKE SAID TRANSDUCER ELEMENT UNDER THE FORCE OF SAID SPRING. 